Question

How does the rain acts as a messenger of mercy in the song of the rain

Answer 1

This is because Rain is pleasant and God give us rain without discrimination so it refer to mercy of one supreme power that is God..

Answer 2

 rain cures the ailment of the clouds by shedding all the burden and quenches the thirst of the field by pouring , motherly love , the water and enriching it.thus it calls itself messenger of mercy

HOPE IT HELPS!